Allthough Nooruls question isn't related to this, i'd like to point out, that the notification is related to the push.
I noticed that when i saw that my custom LED color wasn't blinking like it should. When your app is in the foreground everything is ok. But when your app is in the backround the custom parts of the notification only work when you send the push via API. When you send the push via FireBase Console they are not working.